Prior art concerning face seal fittings does not recognize or address the problem of torque that can adversely affect the components of a fitting and is a factor in the introduction of undesirable particulate matter into a system. Torque is applied to a fitting by the rotation of threaded coupling nuts that engage flanges near the ends of conduits which are drawn together. In the prior art, torque applied to a flange or flange equivalent is transmitted to the seal components which typically consist of axial projecting annular integral sealing beads on the ends of each conduit and an annular gasket. In high temperature and in ultra-clean room applications all of the seal components are typically comprised of metal.
Various means have been developed in the prior art to ensure the position of the gasket is properly aligned with the integral beads of the conduits. If the conduits and gaskets are not properly aligned when the components are drawn together by coupling nuts, a gas tight seal is not achieved. The prior art developments focus on means to align and position the gasket and sealing beads to prevent the conduits from laterally moving to a position off the central axis of the conduits.
The present invention recognizes that torque on the fitting results in both lateral and rotational movement causing the misalignment of the fitting and uneven application of force to the gasket. Both rotational movement and lateral movement from the central axis can cause a faulty seal and the deterioration of the seal components subject to the forces. In addition to its contribution to improper sealing, the deterioration of the integral sealing beads and gasket can introduce undesirable particulate matter into an ultra-clean system. Microscopic examination reveals that scratches on the surfaces of the metal interfaces are reduced when the torque applied to the conduits in interconnecting the fittings is reduced. Further, the deterioration of the system's components requires increased maintenance and replacement parts resulting in more downtime and expense.
Accordingly it is desirable to provide a fitting in which the torque acting on the conduits of a face seal fitting are reduced.
An additional problem encountered with the coupling of conduits is that an integral flange on the conduit will prevent the slipping of a coupling nut over the end of which it is intended to engage. Thus, a threaded nut used to draw the components of a fitting together must be assembled by inserting the coupling device over the conduit from a free end. For components used in ultra-clean environments such as are required in the semi-conductor industry it is undesirable to assemble the coupling device in this manner because it requires that the free end of the conduit be connected and welded in the fluid system after the coupling nut has been assembled over the flanged component of the fitting requiring an increased length of the flanged component to permit the required welding with the coupling nut in place. Integral flanges of the prior art prevent a threaded coupling from slipping over the end of a conduit that is intended to be sealed.
Accordingly, the object of the invention is to construct a conduit fitting assembly that will reduce torque applied to a fitting while providing the additional advantage of allowing the coupling nut to be assembled by slipping the nut over the end of the conduit which is intended to be sealed.
Another object of the invention is to provide a conduit connection having a novel clamping and sealing structure, including a novel split ring with a diamond coating which rotates around a conduit in an annular groove thereby reducing torque forces on the conduit brought on by threaded coupling nuts.
Another object of the invention is to provide a conduit connector that is capable of assembly in a compact area.
Another object of the invention is provide a conduit connection suitable for use in conduits designed for use in ultra-clean environments such as those required in the semi-conductor industry.
A further object of the invention is to provide a method of sealing two conduits by a threaded coupling device which reduces the torque exerted on the conduits and the gasket member.
Further objects and advantages of the invention will be apparent from the following specification, appended claims and accompanying drawings.